移动宽带多址接入系统的峰均功率比研究

发布时间：2018-07-05 20:58

本文选题：高峰值 + PAPR抑制　；参考：《江西理工大学》2017年硕士论文

【摘要】：随着WiMAX(Worldwide Interoperability for Microware Access)和LTE(Long Term Evolution)被确认为IMT-Advanced 4G的标准,移动宽带给大众带来了高速的无线数据传输体验,作为第四代移动宽带多址技术的核心技术,OFDM技术以其调制解调简单,传输容量较大等优点备受关注。但OFDM的一个很明显的缺点是调制后时域信号会出现高峰值,导致功率放大器需要较大的线性变化范围,从而增加放大器的负担。因此本文围绕OFDM峰均功率比的抑制问题,在讨论已有的几种算法后,提出一种改进的峰均功率比抑制算法。首先介绍了移动宽带多址接入系统的概念,以及第四代移动宽带正交频分多址接入系统的构成,比较了正交频分多址与CSMA-OFDM、TDMA-OFDM、FDMA-OFDM在频谱资源分配上的不同。正交频分多址主要由两部分组成:资源分配和OFDM,因此接着重点讨论了正交频分多址系统中OFDM的IFFT/FFT、同步等关键技术。对OFDM的改进技术OFDM/OQAM的分析显示该技术在符号间干扰和载波间干扰、频谱利用率较低、频偏敏感等问题上得到了一些改善,这对未来多址技术的研究具有一定参考作用。然后分析和仿真了OFDM峰均功率比过大的原因是各路子信号同相叠加导致时域信号出现高峰值,而高峰值又能通过信号的相关性来检测。针对OFDM峰均比过高的问题,研究了预畸变类和非畸变类方法中几种常见的抑制峰均功率比的算法,着重讨论了选择映射法、部分传输序列法和限幅法在功率利用效率、频谱利用率、计算复杂的程度和传输性能上各自的优缺点,并通过仿真加以分析。OFMD/OQAM是一种多载波调制(Multi-Carrier Modulation,MCM),峰均功率比过大的问题同样存在,对此分析和仿真了OFDM与OFDM/OQAM在峰均功率比上的异同点。最后根据限幅滤波法和改进的部分传输序列法,提出了一种将二者结合的联合算法,仿真证明该算法既没有增加太大计算度,又能显著降低限幅带来的失真。
[Abstract]:With the recognition of WiMAX (Worldwide Interoperability for Microware Access) and long term Evolution (LTE) as the standard of IMT-Advanced 4G, mobile broadband brings high-speed wireless data transmission experience to the public. As the core technology of the fourth generation mobile broadband multiple access technology, OFDM technology is simple for its modulation and demodulation. The advantages of large transmission capacity have attracted much attention. However, one of the obvious disadvantages of OFDM is that the time domain signal will appear high peak value after modulation, which leads to a large linear range of power amplifier, thus increasing the burden of amplifier. Therefore, in this paper, an improved PAPR suppression algorithm is proposed after discussing several existing algorithms around the PAPR suppression problem in OFDM. This paper first introduces the concept of mobile broadband multiple access system and the composition of the fourth generation mobile broadband orthogonal frequency division multiple access system, and compares the difference between orthogonal frequency division multiple access and CSMA-OFDM TDMA-OFDM FDMA-OFDM in spectrum resource allocation. Orthogonal frequency division multiple access (OFDM) consists of two parts: resource allocation and OFDM. Therefore, the key technologies of OFDM in OFDM, such as IFFT / FFTFT, synchronization and so on, are discussed in detail. The analysis of OFDM / OQAM, an improved OFDM technique, shows that this technique has some improvements in the problems of inter-symbol interference and inter-carrier interference, low spectral efficiency and sensitivity of frequency offset, which is useful for the future research of multiple access technology. Then we analyze and simulate the reason why the PAPR of OFDM is too large because of the high peak value of time domain signal caused by the same phase superposition of each sub-signal and the high peak value can be detected by the correlation of the signal. In order to solve the problem of high peak-to-average ratio (PAPR) of OFDM, several common algorithms of PAPR suppression in predistortion class and non-distortion class are studied, and the power utilization efficiency of selective mapping method, partial transmission sequence method and amplitude limiting method are discussed emphatically. The advantages and disadvantages of spectrum efficiency, computational complexity and transmission performance are analyzed by simulation. OFMD / OQAM is a kind of Multi-Carrier Modulation (MCM), and the problem of excessive peak-to-average power ratio (PAPR) also exists. The difference between OFDM and OFDM / OQAM in peak-to-average power ratio (PAPR) is analyzed and simulated. Finally, according to the amplitude limiting filtering method and the improved partial transmission sequence method, a joint algorithm combining the two methods is proposed. The simulation results show that the algorithm can not only increase the calculation degree but also significantly reduce the distortion caused by the amplitude limit.
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.53

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